theorem Th29:
  Basel-seq.n = 1 / (n^2)
  proof
    rseq(0,1,1,0).n = 1/n by Lm16;
    hence Basel-seq.n = (1/n)*(1/n) by VALUED_1:5
    .= (1*1)/(n*n) by XCMPLX_1:76
    .= 1 / (n^2);
  end;
